ACE No. Ll^LOT 
 
 NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS 
 
 WARTIME REPORT 
 
 ORIGINALLY ISSUED 
 
 Deceniber I9UJ1 aa 
 
 Advance Confidential Report L4L07 
 
 CLBffi AMD HIGH-SPEED TESTS OF A CURTISS NO. 7U-1C2-12 
 FOUR-BLADE PROPELIER ON THE REPUBLIC P-^TC AIEPLAKE 
 By A. W. Vogelej 
 
 Langley Memorial Aeronautical Laboratory 
 Langley Field, Va. 
 
 UNIVERSITY OF FLORIDA 
 
 DOCUMENTS DEPARTMENT 
 
 1 20 MARSTON SCIENCE LIBRARY 
 
 P.O. BOX 117011 
 
 GAINESVILLE. FL 32611-7011 USA 
 
 NACA 
 
 WASHINGTON 
 
 NACA WARTIME REPORTS are reprints of papers originally issued to provide rapid distribution of 
 advance research results to an authorized group requiring them for the war effort. They were pre- 
 viously held under a security status but are now unclassified. Some of these reports were not tech- 
 nically edited. All have been reproduced without change in order to expedite general distribution. 
 
 L - 177 
 
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 http://www.archive.org/details/climbhighspeedteOOIang 
 
I ?.Gf 5 - i i 
 
 1^0 
 
 lkk(:k ACR No. Li+L07 
 
 NATIONAL ADVISORY COMaTTEE FOR AERONAUTICS 
 
 ADViiNCE CONFIDENTIAL REPORT 
 
 CLIMB AlO lilGH-SPEED TESTS OP A CURTISS NO. 71.^--1C2-12 
 FOUR-BLADE PROPELLER ON THE REPUBLIC P-i-J-7C AIRPLANE 
 
 3y A. Vif. Vogeley 
 
 SmiMARY 
 
 Plight tests were made of a Curtlss No. 7ll|-lC2-12 
 four-Llade propeller on a ?lepublic P-/_|-7C airplane in 
 climb and at high speed. The loss in efficienoy v;/hen 
 power v;as increased from normal to military was found to 
 be from ^ to ?:> percent in climbs at an indicated airspeed 
 of 165 m.iles per hour. This loss was attributed primarily 
 to reductions in section lift-drag ratios resulting from 
 increased operating lii't coefficients. 
 
 In high-speed flight at m.illtary power, losses in 
 efficiency due to compressibility started at an airplane 
 Mach numiber less than O.I4. and increased steadily to 10 
 or 11 percent at an airplane Mach number of 0,7. These 
 losses were encountered whenever the prooeller-tip Mach 
 number exceeded 0.83 and the propeller efficiency 
 decreased at a rate of about 7 percent for an increase 
 of 0.1 in tip Mach number. At an airplane Mach number 
 of 0.7 S-nd constant propeller rotational speed the 
 propeller efficiency decreased with a decrease in power 
 below military povver. In comparison with the efficiencies 
 of low- speed flight tests (a Mach number of approxi- 
 mately 0.3) at the same advance-diameter ratio, however, 
 the compressibility loss was relatively independent of 
 power . 
 
 The tests indicated that, by suitably increasing the 
 solidity and reducing the rotational speed, it may be 
 possible to improve the propeller efficiency in both 
 climb and high-speed operation. 
 
CONFIDETfriAL NACA ACR No. L^LO? 
 lA^THOLUCTTON 
 
 Ar pax't of a pro£:i8^ri of flight tests of several 
 nropellers en the Keoubllc v-IlJC airplane for tne purpose 
 of dett-rmlning clirn'o u.nd high-speed characteristics, 
 tests have been i.jede of a Ciirtiss No. 71M--1C2-12 four- 
 blade prooeller. Results of these tests and a brief 
 analvijis ax'c presented herein. 
 
 The climb tests consisted of runs at normal rated 
 ■oower, indicated airspeeds of l5o and 165 miles per hour, 
 and altitudes froiri sea level to about ^0,00G feet and 
 runs at iiiilitarjr power, an indicated airspeed of 165 miles 
 per hour, and altitudes froni sea level to about ^5,000 feet 
 High-speed tests consisted of a series of i^uns covering 
 a Mach number ran^-e from J.L. to 0.7 at approximately 
 constant p^v.-er and rotatioufl speed and a series of runs 
 at a Ilach nixmber of O.7 and constant rotational speed 
 with varying power. In order to determine the affects 
 of co..ipi-es3ibility, the efficiencies measured in the 
 high-speed runs were compared with those -rieasured in runs 
 made at the sa.ne rower coefficient and advance -diameter 
 ratio but at a Mach namler of ao'^ut O.J, 
 
 SysPOLS 
 
 V true airspeed 
 
 n propeller rotational speed, revolutions per 
 second 
 
 D propeller diameter 
 
 -T advance-diameter ratio {V/nD) 
 
 [i section blade angle at 0.75R 
 
 9 blade angle at any section 
 
 R pro poller- tip radius 
 
 V propeller-section radius 
 b blade- section chord 
 
 CONFIDENTIAL 
 
 1 
 
KACA aCR j'lo. r'lLO'; 
 
 GCNFIDEI^TIaL 
 
 2; 
 
 h 
 
 blr.de - se ct ion tlii ckne ss 
 
 radial distance from thrust axis to survey point 
 
 P-p, 
 
 Ap.-p 
 
 Cp 
 
 P 
 
 ¥ 
 
 Kt 
 
 R 
 
 free-strea.T! ctatic pressure 
 free -stream "cctal pressure 
 
 difference betv^feen sliostrearu total pressure and 
 free-streani total pressure 
 
 ororeller thi'ust 
 
 ■oroceller torque 
 
 propeller thi'ust coefficient 
 
 propeller po»'er coefficj ent 
 
 r»ropeller efi'iciency 
 
 ratio of asnsLtj of free air to density of air 
 at sea level 
 
 density of free air 
 
 airolane Mach number 
 
 proTDeller-tip Vach number 
 
 PROPELLER AKD TEST EQUIPMENT 
 
 General specifications of the propeller and power 
 ■Dlant are as follows: 
 
 Number of blades . . 
 Blade design .... 
 Blade se:;tlon.3 . . . 
 propeller diaaeter . 
 Propeller gear i-atio 
 En.siine ....... 
 
 . . . . . ...... Pour 
 
 . Curtiss No. 7.1 J+- 102- 12 
 .......... Clark Y 
 
 . . . . 12 feet, 2 inches 
 
 ........... 2:1 
 
 Pratt ic VVnitnev R-2300-21 
 
 COUPIDEaTTIAL 
 
Ij. COKFTDEKTIAL IIACA ACR No. Li;L07 
 
 Military-povjer rating of ongine : 
 
 Engine speed, rpm 27OO 
 
 Manifold pressure, inches of mercury ^2 
 
 Horsepower 2000 
 
 Critical eltitude, feet (approx.) 1^,000 
 
 i\-ormai-power rating of engine : 
 
 Engine speed, rpni 255^ 
 
 Manifold prescure, Incnes of mercury J4.2 
 
 Horsepower lo25 
 
 Critical altitude^ feet . (approx.) Z^,000 
 
 The propeller, as tested, was equipped v-ith the standard 
 production cooling cuffs. Biade-forTi curves are presented 
 in figure 1. 
 
 propeller thrust was measured by the slipstream. 
 total-pr-es3ure sui'vey r.^ethod. For tnls purpose tv/c survey 
 rakes J connected tc NIG/ rocoi-dlng multiple menoneters, 
 were mounted horizontally on either side of the fuselage 
 at the rear of the engine coi.-llng, as shown in figure 2. 
 A photograph of uhe alrplan^^, pi'-opeller, ana survey rakes 
 is presented as figure 5. 
 
 propeller toi-qua v/es -nessured with a standard 
 Pratt & Whitney torque meter, to v;hicn was connected a 
 standard NACA pressure recorder. An indicating pressure 
 gage was mounted in tiie cockpit for use by the pilot. 
 Standard NACA recording Instrui-nents were used to record 
 engine speedy, impact pressure, static pressure, and free- 
 air temperature. Propeller blade angle was m.easui-ed 
 with a special NACA spark -type biade -angle recorder. 
 
 TEST PROCED0P.es 
 
 Climb t ests . - 'Aith engine speed, m:.8nifold pressure, 
 and inalcated airspeed adjusted to the desired values, 
 short records on all instruments were tfken at intervals 
 of 2000 feet as the airplane climbed frcm sea level to 
 altitude . 
 
 Climbs were m.ade under the following conditions: 
 
 (1) Militar:/ pcwer at normal climbing indicated airspeed 
 of 165 m.iles per hour 
 
 CONFIDSI'TTIAL 
 
NACA'ACRNo. Ll+LOy CONFIDENT T....L 5 
 
 (2) Nonral T:.ower at Indicated airspeed of l60 miles -oer 
 hour 
 
 (5) Normal power at indicated airspeed of 165 miles per 
 hour 
 
 ';^he climb at military power v/as terminated at the 
 relacively low iHitaie of 25,000 feet te'^:^.Ll,<:e of 
 insufficient eac^-;:,ne cooling indicated by nigr-. cylinder- 
 head 'ceniperat-ure . 
 
 High-speed tests.- Each high-speed run was made at 
 value 'T of en£-ine~~3pe5d. torque, indicated airspeed, and 
 pressure altitude selected to produce a desired combination 
 of values of aii-Dlane I,"ach number, propeller advance - 
 diamecer ratio, and power coefficient. Because the air- 
 olane v.-as usvxaily either clim.bing or diving during a run, 
 only engine speed, torque, and airspeed coula be fixed. 
 These values were therefore held constant as the airplane 
 passed through the desired altitude, when a shore record 
 ■.vas taken. 
 
 The low-speed runs (''I '~ O.5), used as a basis for 
 determining the effects of compressibility, were miade in 
 the same manner as the high-speed runs. 
 
 REDUCTION 07 DAT. 
 
 True airsDeed, airplane Mach number, and air density 
 were obtained by standard reduction methods from the 
 recorded values of imoact oressure, static pressure, and 
 indicated free -air temperature. Engine speed, torque, 
 and propeller blade angle were recorded directly. 
 
 Propeller povi?er coefficient was calcultited by the 
 formula 
 
 Cp - 
 
 pn^D'^ 
 
 ProTjeller-tip Mach numbei' was obtained from the 
 equation 
 
 .t = v^ . (5) , 
 
 r<r)-KTTrTDTr!''^'T'''' AT, 
 
CONFIDENTIAL NACA ACR No. l1;L07 
 
 Propeller thrust coerficlert was evalueted fron the 
 measureraents of sllpstre.arri total pressure by the method 
 descrlbsd In reference 1, v.hich gives 
 
 dT 
 
 -4s^) V^^^c 
 
 1) 
 
 In order to obtein tie nondimer.sional quantities used in 
 the present report, equation (Ij was reduced as follows: 
 
 ^'^T dT TT 
 
 d 
 
 Tne areas under the curv3S of dCrp/d(x„'^ ) against Xg 
 are equal to the thrust coefficients. 
 
 RESUTJS AfIB DISCUSSION 
 
 Climb test:- . - The variations of blade an^^le, 
 advance-diametei- ratio, power &nd thrust coefficients, 
 ef :''iciency, and propeller-tip and airplane Pv'ach numbers 
 v;ith density altitude for the clira.bs are presented in 
 figures -'j. to 6. There flight data ai'e also given in 
 taole I. 
 
 In each of the cliffibs, changes In propeller effi- 
 ciency with altitude pppenr to be smsll. Except for a 
 slight initial increase, efficiency tends to decrease 
 with albitude. This decrease is to be expected, since 
 the operating lilt coefficients of the blade sections 
 Increase with iiicreasing altitude and approach the stall 
 region] the final result is to reduce the section lift- 
 drag ratios and to lower the efficiency. 
 
 Compressibility effects become evident in each of 
 the climbs whenever the propeller-tip mach number exceeds 
 about 0,06. Thrust-grading curves for climb at normal 
 power and an indicated airspeed of 1(;0 miles per hour 
 are presented in figure 7 to show these effects of 
 compressibility at high propeller-tip Mach numbers. The 
 effects ol compressibility are not evident in runs 
 20-1 to 20-11, in which tip Mach mombers are below O.65 
 (figs. 7(a) to 7(f)). The first effects are evident on 
 
 CONFIDENTIAL 
 
HACA rtCR No. Li|L07 CONFIDENTIAL 7 
 
 the right side of the propeller disk for run 20-12 
 (fig. 7(g)) 5 in which the tip Mach number has reached 0.86. 
 These effects continue to increase with tip Kach number. 
 Little or no evidence of coiapressibllity loss exists on 
 the left side of the propeller disk, probably because the 
 left side is less heavily loaded than the right side 
 owing to inrilination of the thrust axis to the air stream. 
 To the extent, therefore, that the disk load distribution 
 is affected, the tip Mach number at which comprescibility 
 effects first become evident is Influenced by the airplane 
 attitude with respect tc the flight path. 
 
 The term, "compressibility effects" as used herein 
 means the effects shown by changes in the general shape 
 of the thrust-grading curves, for examnle, the dip in 
 the curve between Xs"^ = 0.6 and xs^ = 0.5 as measured 
 
 with the right survey rake in run 20-15 (fig- 7(h)). The 
 term does not incD.ude the effect that causes the grading 
 curves for both the right and left surveys to approach 
 zero at the tip at different values of Xg^. This effect 
 
 is directly attributable to an unintentional yawed 
 attitude of the airplane held during the run, which 
 causes the slipstream to be displaced laterally at the 
 survey rakes. 
 
 Losses in thrust due to compressibility are present 
 at the higher tip Mach numbers but no marked decrease in 
 efficiency attributable to this cause is apparent. w'ith 
 further increases in altitude that result in higher 
 section lift coefficients and Mach numbers, hovirever, it is 
 expected that the losses wou].d extend over an increasing 
 part of the disk area and that the effect on efficiency 
 would becomxe significant. Compressibility losses can be 
 delayed by reducing the tip blade angles. This reduction 
 would result in a transfer of load to the inboard sections, 
 viThich operate at lovi/er Mach numbers and can therefore 
 absorb the additional load without serious compressibility 
 effects. The inboard shaft of load would also tend to 
 bring the blade loading into closer agreement with the 
 theoretically/ ideal load distribution for a pi'opeller 
 operating at low advance-diam_eter ratios; thus the 
 possibility of a reduction in induced losses exists. The 
 use of this miethod is suggested only if particular emphasis 
 is put on climb perf orm.ance , since large losses in efficiency 
 at high speed may result. 
 
 Since in the range of advance-diameter ratio for 
 clim.b the propeller operates at power coefficients greater 
 
 CONFIDENTIAL 
 
CONhTDENTTAL NACA ACR No . Lij.L07 
 
 than the values for maxi.ir.ini efficiency, it is £i;enerally 
 recognized that eitner a reduction in power coeflicient 
 or an increase in advance -diameter ratio is necessary to 
 increase efficiency. These methods are illustrated by 
 comparing the efficiency levels (at tip Wiach numbers 
 below 0.86) of the climbs (figs, [i to t) . 
 
 In the rrilitary-DOwer cli'^b (fi^. I;), the propeller 
 operates at an efficiency of about 7t> percc-nt. By 
 I'educing the power coefficient at essentially the sairie 
 advance-dian'e tsr ratio, as in the normal -pov;er climb at 
 an indicated airspeed of l60 miles per hour (fig. 5)» the 
 propeller efficiency is increased to approximately 
 80 percent. An additional gain in efficiency of about 
 5 oercent is achieved by Increasing the airplane speed 
 and thereby increas-*_ng bhe advance -dianieter ratio, as in 
 the climb of figure o. These gains in efficiency are 
 due primarily to reductions in the section lift coef- 
 ficients that cause the sections to operate at lift-diag 
 ratios anoroaching the optimum.. The climb perform.ance 
 of the airplane is, of course, not im.proved bj the 
 increase in nroDeller efficiency because of the large 
 reduction in oovver required to effect the Increase. Jn 
 order to improve the airplane climb oerform.ance , a 
 prorieller designed to absorb military power at these 
 higher section lift-drag ratios is necessary; in effect, 
 an increase in solidity is required. 
 
 H igh-3'oeed test s.- In order to determine tiie effects 
 of compressibility on prooeller operation at constant 
 power, two series of i-uns v.'ere made at airplane 
 ¥ach numbers ranging from .Ij- to O.7. One series v^as 
 made at a povver coefficient of about 0.33> which 
 corresponds apnroximatel;^ to military-power operation at 
 critical altitude {^'J.OOb ft). The second series v.-as 
 made at a pov^er coefficient of about O.29, \mich 
 corresponds to m.ilitary oower at an altitude of about 
 iSjOOO feet. The data obtained in these tests are given 
 in table II. 
 
 The pi-cpeller ex'f iciencies measured at high speeds 
 are compared in figure 8 with the efficiencies measured 
 at low spced (F ~ O.J) in runs covering the same 
 ranges of power coefficient and advance-diameter ratio. 
 The lowf-speed tests are surrmiarized in figure 9> v.'hich 
 shows the variation of propeller efficiency with power 
 coefficient and advance-diameter ratio. 
 
 CONFIDENTIAL 
 
NACa ACR No. lI^LO? CONFIDENTIAL 9 
 
 At the oroDeller s-oeed used, in the runs of figure 8, 
 losses in efficiency due to compressibility apparently 
 tegln at an airolane Mach number below O.Li, increase 
 steadily, and reach 10- to 1]. percent at an airplane 
 Mach number of U.7. The corresponding propeller-tip 
 Kach numbers range from about O.95 to I.07. 
 
 The effect of propeller- tip Mach number on efficiency 
 is shown in figure 10, in which the ratio of high-speed 
 efficienc7f to low-speed efficiency is given as a function 
 of >he high-speed propeller-tip Mach numoer. Figure 10 
 shows that losses in efficiency begin at Mt = 0.38, 
 which is in close agreement v/ith the results of the 
 climb tests. The efficiency loss due to compressibility 
 is shov/n to increase at the rate of about 7 percent for 
 an increase of 0.1 in tip Kach number. 
 
 Thrust-grading curves of runs at a power coefficient 
 of 0.35 3-1^6 presented in figure 11. As in the climb 
 runs, only the right side of the propeller disk shows 
 any apprecisble compressibility loss (fig. 11(a)). As 
 the Mach num.ber is increased, nowever, compressibility 
 losses also beconi.e evident on the left side (fig. 11(b)). 
 With further increase in Mach number, the losses becom.e 
 larger and extend inboard over a greater portion of the 
 propeller blade. 
 
 The thrust-grading cui'-ve of a run made at an 
 airolane Mach number of about O.5 and at a reduced 
 rotational speed is presented in figure 12. The advance- 
 diameter ratio and oower coefficient are approxim.ately 
 the sam=e as those of figure 11(f), The marked difference 
 in the shape . of these grading curves indicates the extent 
 of the losses in the high-speed run of figure 11(f). 
 Figure 12 may also be com.oared vi'lth figure 11(b). These 
 two runs were made at roughly the same power coefficient 
 and airplane Mach number. The curves for the two runs 
 illustrate how compressibility losses may be reduced by 
 decreasing the propeller rotational speed and thereby 
 reducing the section Mach numbers. By reducing the 
 rotational speed, the propeller efficiency is increased 
 about L percent or about one -half the Increase to be 
 expected from the reduction in tip Maeh number alone 
 (fig. 10). This difference indicates that the propeller- 
 tip Mach numiber alone does not determine the magnitude 
 of the comipressibility losses. 
 
 CONFIDENTIAL 
 
10 CONFIDENTIAL MCA ACR Ho. I^-LO? 
 
 The effect of loading on the prupeller efficiency 
 at high sneed was investigated "by making a series of runs 
 at an airrilane I.iach number of about 0.7 and constant 
 nrooeller speed with varying r)ower. The results of these 
 tests are compared in figure IJ with the results taken 
 from figure 9 '^^ low-speed tescs at the same advance- 
 dia?neter- ratio and pov,'er coefficients. The extrapolated, 
 point in figure IJ was determined, by first extending the 
 curve for the high-speed tests (Cp :: 0.55) in figure 8 
 to an airolane Mach number of 0.7 and an advance-diameter 
 ratio of 2.6. The value of efficiency obtained was then 
 corrected to an advance-diameter ratio of 2.7 by using 
 the curve for the low-speed tests (Cp - 0.55) of" 
 
 figure S. As the cower Is reduced the propeller 
 efficiency decreases at both low and high speeds. The 
 compressibility loss at high speed, as measured by the 
 diffei-ence in high-speed and low-speed, efficiency, appears 
 to be relatively independent of povver and is about 
 10 to li| percent throughout the rango investigated. 
 
 The effect of compressibility is to reduce the lift 
 coefficient for maximum section efficiency as the critical 
 Lach number is exceeded. A decrease in po'vver would, 
 consequently, be expected to cause a reduccion in 
 comores sibi lity loss. In this case, however, some 
 sections of the propeller are apinarently operating at 
 approximiately maximum efficiency and som.e, at lift coef- 
 ficients above those for maxim.um efficiency. Under such 
 circuniPtances a reduction in power would result in a 
 decrease in efficiency of so.me sections and an improvement 
 in efficiency in others; the over-all effect vould be 
 only a small change in compressibility loss. Figure lU 
 shows that the tip sections are operating at highest 
 efficiency at high Dower, since' as the power is reduced 
 the tip sections prodvice a decreasing amiount of thrust 
 in comparison with tne inboard sections. Some gain in 
 high-speed efficiency could rrobably be obtained by an 
 adjucjtment in load distribution. 
 
 A comparison of the results of the high-speed and 
 low-speed tests indicates that. In order to prevent 
 large losses in efficiency, blade-section Mach numbers 
 m.ust be limited by reducing the rotational speed. At the 
 sam.e time, however, any adverse effect due to the 
 increase in section lift coel'f icients necessary to 
 absorb the same engine power at a lower rotational speed 
 must be avoided by a proper increase in propeller solidity. 
 
 CONFIDENTIAL 
 
NACA ACR No. Li|L07 CONFIDENTIAL 11 
 
 CONCLUSIONS 
 
 Plight tests of the Gurtiss No. 7li4.-lC2-12 four- 
 blade propeller on a Republic P-ij-YC airplane indicated 
 the following conclusions: 
 
 1. In climbs at an indicated airspeed of 165 miles 
 per hour^ from S to 8 percent was lost in efficiency by- 
 increasing from normal to military power, primarily 
 because of the reductions in section lift-drag ratio that 
 resulted from increased operating lift coefficients. 
 
 2. '\i1:ith military DOwer, losses in efficiency due 
 to compressibility started at an airplane Mach number 
 less than O.ls, increased steadily, and reached 10 
 
 to 11 percent at an airplane Mach number of 0.7. Compressi- 
 bility losses becajue evident whenever the propeller-tip 
 Mach number exceeded about 0.88, and the propeller 
 efficiency docreased at a rate of about 7 percent for an 
 increase of 0.1 in tip I.Tach number. 
 
 3. At an airplane Mach number of O.7, a reduction 
 in engine power below military power resulted in a lower 
 propeller efficiencjr, but the loss in efficiency due to 
 compressibility (based on low-speed tests at a corre- 
 sponding advance-dlam.eter ratio) was relatively independent 
 of power. 
 
 Ij.. By suitably increasing the solidity and reducing 
 the rotational speed, an improvement in the propeller 
 efficiency in both climb and high-speed operation m.ay be 
 possible . 
 
 Langley Memorial Aeronautical Laboratory 
 
 National Advisory Committee for Aeronautics 
 Langley I-'leld, Va . 
 
 REFERENCE 
 
 1. Vogeley, A. W , : Flight Measurements of Compressi- 
 bility Effects on a Three-Blade Thin Clark Y 
 Propeller Operating at Constant Advance-Diameter 
 Ratio and Blade Angle. NACA ACR No. 3G12, I9I4.5 . 
 
 CONFIDENTIAL 
 
I 
 
NACA ACR No. L4L07 
 
 12 
 
 TABLE I 
 
 PLIGHT DATA OBTAINED FROM CLIMB TESTS OP 
 
 CURTISS NO. 711^.-102-12 POUR-BLADE PROPELLER 
 
 Pig. 
 
 Run 
 
 J 
 
 Cp 
 
 Cip 
 
 Tl 
 
 n 
 
 (rps) 
 
 K 1 
 
 * 
 
 t 
 
 a 
 
 (dag) 
 
 h 
 
 29-1 
 
 °:l't 
 
 0.11^6 
 
 0.122 
 
 0.783 
 
 22.52 
 
 .235 0. 
 .240 
 
 812 0, 
 
 025 
 
 26.6 
 
 k 
 
 29-2 
 
 .179 
 .1S7 
 
 .159 
 .ili5 
 
 .750 
 
 22.65 
 
 818 
 
 858 
 
 28.4 
 
 k 
 
 29-3 
 29-U 
 
 .99 
 
 :?^^ 
 
 22.62 
 
 246 
 
 823 . 
 
 805 
 
 28.9 
 
 h 
 
 1.02 
 
 .200 
 
 .151 
 
 22.14 
 
 264 
 
 82S . 
 
 845 
 
 756 
 
 29.9 
 
 h 
 
 29-5 
 
 1.05 
 
 .212 
 
 'I5k 
 
 .761 
 
 22.50 
 22.1+4 
 
 799 
 
 50.8 
 
 h 
 
 29-6 
 
 1.08 
 
 .230 
 
 .160 
 
 .750 
 
 .264 
 
 662 
 
 51.6 
 
 k 
 
 29-7 
 
 29-8 
 
 1.12 
 
 .238 
 
 .162 
 
 .758 
 
 22.57 
 
 §50 
 
 629 
 
 52.4 
 
 k 
 
 1.15 
 
 .253 
 
 .165 
 
 .736 
 .7^ 
 
 22.54 
 
 ,290 
 
 §^9 
 
 592 
 
 55.5 
 ^4.5 
 
 k 
 
 29-9 
 
 1.19 
 
 .273 
 .289 
 
 •^71 
 
 22.49 
 
 .306 
 
 g^5 
 
 555 
 
 k 
 
 29-10 
 
 1.22 
 
 .178 
 
 .749 
 
 22.61 
 
 .520 . 
 
 882 
 
 512 
 .489 
 
 55.2 
 
 h 
 
 29-11 
 
 1.26 
 
 .302 
 
 .179 
 
 .7U8 
 
 22.49 
 
 .554 
 
 .896 
 
 56.2 
 
 3, 7(a) 
 
 20-1 
 
 .9U 
 
 .11^0 
 
 .116 
 
 .779 
 .798 
 
 21.21 
 
 225 
 
 782 
 
 968 
 
 26.4 
 27.6 
 28.6 
 
 5 
 
 20-2 
 
 .99 
 
 .150 
 
 .121 
 
 21.29 
 
 .237 
 .240 
 
 .790 . 
 
 903 
 
 5. 7(b) 
 
 20-3 
 20-It. 
 
 1.00 
 
 .165 
 
 .132 
 
 .lll6 
 
 .799 
 .810 
 
 21.56 
 
 795 
 
 858 
 
 5 
 
 1.06 
 
 .191 
 
 21.20 
 
 .254 
 
 792 
 812 
 
 775 
 
 50.2 
 
 5, 7(c) 
 
 20-5 
 
 1.08 
 
 .189 
 
 .140 
 
 .798 
 .802 
 
 21.52 
 
 .263 
 
 751 
 
 50.4 
 
 5 
 
 20-6 
 
 1.09 
 
 .195 
 
 .11^3 
 
 21.73 
 
 .271 
 
 828 
 
 692 
 .648 
 
 51.1 
 
 5, 7(d) 
 
 20-7 
 20-8 
 
 1.15 
 
 .213 
 
 .150 
 
 .806 
 
 21.49 
 
 .284 
 
 825 
 
 52.2 
 
 5 
 
 1.17 
 
 .228 
 
 .156 
 
 .799 
 
 21.50 
 
 .290 
 
 849 
 
 .610 
 
 52.q 
 
 5, 7(e) 
 
 20-9 
 
 1.20 
 
 .2l|0 
 
 •1^? 
 
 .790 
 .813 
 
 21.74 
 
 .302 . 
 
 .566 
 
 Hi 
 
 5 
 
 20-10 
 
 1.26 
 
 .261 
 
 .168 
 
 21.52 
 
 21.45 
 
 517 
 
 .852 
 
 .528 
 
 5, 7(f) 
 
 20-11 
 
 1.28 
 
 .272 
 
 .168 
 
 .791 
 
 525 . 
 
 §52 
 
 .506 
 
 .467 
 
 35. 3 
 
 5, 7(g) 
 
 20-12 
 
 1.36 
 I.UI 
 
 .303 
 
 .178 
 
 •799 
 .808 
 
 21.15 
 
 21.14 
 
 542 
 
 861 
 
 57.0 
 
 5 
 
 20-15 
 20-14 
 20-15 
 
 .518 
 
 .135 
 
 357 
 
 374 
 
 424 
 
 37.. 8 
 
 5 
 5, 7(h) 
 
 It 
 
 ■M 
 
 .185 
 .136 
 
 .786 
 .787 
 .816 
 
 21.48 
 
 :Wb 
 
 891 
 920 
 
 'M 
 
 39.1 
 
 4o.o 
 
 6 
 
 18-1 
 
 1.00 
 
 .lU5 
 
 .113 
 
 21.25 
 
 M 
 
 .780 
 
 M 
 
 27.2 
 28.0 
 
 6 
 
 18-2 
 
 1.01 
 
 .158 
 
 .126 
 
 .809 
 
 21.57 
 
 788 
 
 6 
 
 18-3 
 18-II 
 
 1.07 
 
 .171 
 
 .133 
 
 .858 
 
 21.16 
 
 .254 
 
 786 
 
 .852 
 
 29.0 
 
 6 
 
 1.11 
 
 .196 
 
 .157 
 .111.5 
 
 .820 
 
 21.56 
 
 .264 
 
 794 
 
 764 
 726 
 
 50.2 
 
 6 
 
 18-5 
 
 1.15 
 
 .81^7 
 
 21.22 
 
 .274 
 
 792 - 
 818 
 
 50.7 
 
 6 
 
 18-6 
 
 1.16 
 
 .205 
 
 .1I4.9 
 
 .81+5 
 
 21.55 
 
 .283 . 
 294 
 
 685 
 
 51.6 
 
 6 
 
 18-7 
 
 1.20 
 
 .220 
 
 .155 
 
 .833 
 
 21.50 
 21.45 
 
 825 
 
 645 
 6o4 
 
 52.4 
 
 6 
 
 18-6 
 
 l.Pli 
 1.28 
 
 .257 
 
 .156 
 
 .819 
 
 305 . 
 
 §?5 . 
 845 . 
 
 m 
 
 6 
 
 18-9 
 
 .252 
 
 .163 
 
 .822 
 
 21.45 
 
 .517 . 
 
 565 
 
 6 
 
 18-10 
 
 1.32 
 
 .269 
 
 .168 
 
 .822 
 
 21.57 . 
 
 550 . 
 
 544 . 
 
 851 . 
 
 551 
 499 
 
 55.5 
 
 6 
 
 18-11 
 
 1.51; 
 
 .279 
 
 .170 
 
 .819 
 
 21.60 
 
 874 
 
 56.2 
 
 6 
 
 18-12 
 
 1.37 
 
 .296 
 
 .176 
 
 .811 
 
 21.48 
 
 550 • 
 
 875 . 
 
 ^70 
 
 57.2 
 58.3 
 
 6 
 
 18-13 
 18-lli. 
 
 .320 
 
 .178 
 
 .791 
 
 21.51 . 
 
 568 . 
 
 8S2 . 
 
 458 
 
 6 
 
 iM 
 
 .332 
 
 .181 
 
 .808 
 
 21.58 . 
 
 589 . 
 4o5 . 
 
 922 . 
 
 ^91 
 584 
 
 ?9-2 
 40.4 
 
 6 
 
 18-15 
 
 1.5^ 
 
 1.5b 
 
 .366 
 
 .191 
 
 .801 
 
 21.40 . 
 
 922 
 
 6 
 
 18-16 
 
 .379 
 
 .186 
 
 .761; 
 
 21.65 
 
 1|?,0 , 
 
 952 
 
 557 
 
 41.2 
 
 NATIONAL ADVISORY 
 COMMITTEE POR AERONAUTICS 
 
NACA ACR No. L4L07 
 
 13 
 
 TABLE II 
 PLIGHT DATA OBTAINED PROM HIGH-SPEED TESTS OP 
 CURTISS NO. 7li<--lC2-12 POUR-BLADE PROPELLER 
 
 Wg. 
 
 Run 
 
 J 
 
 Cp 
 
 Crp 
 
 T| 
 
 n 
 
 (rpa) 
 
 M 
 
 Mt 
 
 
 
 (deg) 
 
 11(a) 
 
 24-6 
 
 1.59 
 
 o.5i;5 
 
 0.171 
 
 0.792 
 
 22.62 
 
 0.451 
 
 0.952 
 
 0.416 
 
 59.8 
 
 11(b) 
 
 24-5 
 
 1.8U 
 
 .5i^7 
 
 .151 
 
 .801 
 
 22.47 
 
 .U95 
 
 .979 
 
 .416 
 
 u.u 
 
 11(c) 
 
 24-1 
 
 2.08 
 
 .552 
 
 .I5i; 
 
 .786 
 
 22.44 
 
 .557 
 
 1.009 
 
 .41B 
 
 hk.l 
 
 11(d) 
 
 2I4.-2 
 
 2.21 
 
 .551 
 
 .121 
 
 .759 
 
 22.46 
 
 .59!^ 
 
 1.055 
 
 .J|22 
 
 1^5.5 
 
 11(e) 
 
 24-5 
 
 2.45 
 
 .558 
 
 .107 
 
 .755 
 
 22.50 
 
 .655 
 
 1.064 
 
 .422 
 
 U7.5 
 
 11(f) 
 
 2k-k 
 
 2.47 
 
 .51^6 
 
 .099 
 
 .708 
 
 22.48 
 
 .666 
 
 1.077 
 
 452 
 
 i+7.9 
 
 ll+(a) 
 
 17-1 
 
 2.69 
 
 .ikk 
 
 .021 
 
 .595 
 
 22.62 
 
 .711 
 
 1.092 
 
 .576 
 
 
 
 
 17-2 
 
 2.77 
 
 .151 
 
 .026 
 
 .482 
 
 22, OS 
 
 .712 
 
 1.075 
 
 .560 
 
 
 
 
 17-5 
 
 2.70 
 
 .164 
 
 .050 
 
 .500 
 
 22.52 
 
 .702 
 
 1.079 
 
 .575 
 
 
 
 ll^(b) 
 
 17-1^ 
 
 2.75 
 
 .176 
 
 .051 
 
 .1^76 
 
 22.20 
 
 .706 
 
 1.077 
 
 .569 
 
 
 
 
 17-5 
 
 2.75 
 
 ,204 
 
 .040 
 
 .5i+5 
 
 22.05 
 
 .705 
 
 1.069 
 
 .557 
 
 
 
 
 18-17 
 
 2.68 
 
 .216 
 
 .051 
 
 .656 
 
 22.50 
 
 .701 
 
 1.078 
 
 .559 
 
 1^7.8 
 
 ll+(c) 
 
 13-18 
 
 2.67 
 
 .221 
 
 .046 
 
 .557 
 
 22.28 
 
 .695 
 
 1.070 
 
 .545 
 
 1+7.8 
 
 
 20-18 
 
 2.58 
 
 .256 
 
 .060 
 
 .609 
 
 25.51 
 
 .699 
 
 1.100 
 
 .551 
 
 1+7.2 
 
 ll4.(d) 
 
 21-9 
 
 2.68 
 
 .282 
 
 .071 
 
 .672 
 
 22.42 
 
 .695 
 
 1.071 
 
 .51+1 
 
 
 
 21-10 
 
 2.55 
 
 .290 
 
 .080 
 
 .704 
 
 22.45 
 
 .662 
 
 1.047 
 
 .521 
 
 
 
 
 21-11 
 
 2.52 
 
 .292 
 
 .096 
 
 .758 
 
 22.47 
 
 .604 
 
 1.015 
 
 .525 
 
 
 
 
 21-12 
 
 2.14 
 
 .291 
 
 .108 
 
 .797 
 
 22.41 
 
 .554 
 
 .984 
 
 .527 
 
 
 
 
 21-15 
 
 1.95 
 
 .295 
 
 .122 
 
 .805 
 
 22.49 
 
 .508 
 
 .960 
 
 .515 
 
 
 12 
 
 12-1 
 
 2.5U 
 
 .550 
 
 .109 
 
 .842 
 
 17.81 
 
 .505 
 
 .805 
 
 .716 
 
 
 
 NATIONAL ADVISORY 
 COMMITTEE FOR AERONAUTICS 
 
NACA ACR No. L4L07 
 
 Pig- 1 
 
 r/^ure I.-B/oc/e-form curtres- for Curhss /Vo. 7/4--/C2'/Z 
 
 four- b/ac/e py-ope//er: 
 

NACA ACR No. L4L07 
 
 Fig. 2 
 
 'Each rake 
 Con fains 2G ioial 
 pressure -hubes 
 
 NATIONAL ADVISORY 
 COMKiniE FOR AEliONAUIKS 
 
 Figure Z.- Locaf ion oi propeller and survey/ rakes or a. f?epu bhc P-4-7C airplane. 
 
NACA ACR No. L4L07 
 
 Fig. 
 
 .—I 
 I 
 
 o 
 
 r— I 
 I 
 
 m 
 
 
 w 
 
 
 ■M 
 
 
 -p 
 
 • 
 
 u 
 
 w 
 
 3 
 
 0) 
 
 o 
 
 ^ 
 
 
 cd 
 
 (ri 
 
 kl 
 
 x; 
 
 >2 
 
 +j 
 
 (U 
 
 •H 
 
 > 
 
 s 
 
 S-, 
 
 
 =s 
 
 XJ 
 
 w 
 
 (U 
 
 
 a.T3 
 
 a- 
 
 c 
 
 •H 
 
 td 
 
 =! 
 
 
 cr 
 
 u 
 
 QJ 
 
 0) 
 
 
 r-t 
 
 OJ 
 
 M 
 
 G 
 
 OJ 
 
 ct3 
 
 p. 
 
 rH 
 
 o 
 
 U 
 
 i-> 
 
 S-i 
 
 (X 
 
 • H 
 
 
 cd 
 
 (D 
 
 
 Td 
 
 o 
 
 cd 
 
 D- 
 
 M 
 
 1 
 
 ^ 
 
 I 
 
 a, 
 
 1 
 
 
 d 
 
 o 
 
 o 
 
 •H 
 
 t(-i 
 
 rH 
 
 
 Xi 
 
 
 :i 
 
 
 (X 
 
 
 (D 
 
 
 Pi 
 
 
 1 
 CO 
 
 
 (D 
 
 
 S-i 
 
 
 3 
 
 
 to 
 
 
fJACA ACR No. L4L07 
 
 Fig. 
 
 fi,deg 
 
 J 
 
 35 
 .30 
 .25 
 .20 
 .15 
 .18 
 .16 
 .// 
 .12 
 90 
 rj, percent gO 
 70 
 1.0 
 
 .9 
 Mi. 
 
 Cr 
 
 ,o 
 
 — — 
 
 n 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 o 
 
 
 G 
 
 n 
 
 Q 
 
 
 _^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 O 
 
 ■ o — 
 
 
 
 o o 
 
 M 
 
 
 
 
 
 
 
 
 
 
 
 -— o— 
 
 -G 
 
 
 
 
 o 
 
 ■^ — 
 
 
 
 — o- 
 
 Q- 
 
 -o- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 NA 
 COMMI' 
 
 riONAL 
 TEE FOR 
 
 iDVISORY 
 AERONAI 
 
 TICS 
 
 '^ 8 12 16 
 
 Densjfy al+ifude , ff 
 
 20 
 
 24 
 
 28 x 10^ 
 
 Figure 4-.- Milifarij -poller climb of an indicated airspeed of 
 /6S mi/es per hour. Curhss No. 7J4--IC2-f2 four- blade 
 propeller on J?e public P-47C airpJane. 
 
NACA ACR No. L4L07 
 
 ■Fig. 5 
 
 /3 ,deg 
 
 J 
 
 Ct 
 
 r),perrxnf 
 
 Mt 
 
 M 
 
 30 
 80 
 70 
 1.0 
 .9 
 .8 
 .7 
 .4 
 J 
 
 
 
 
 
 o 
 
 ^ 
 
 
 
 
 
 3 
 
 
 
 P) 
 
 
 
 o- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 00 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 a 
 
 
 
 
 
 
 
 
 , ^ 
 
 
 '■ 
 
 3- 
 
 ^ 
 
 
 
 
 TT— 
 
 tj 
 
 
 
 O— 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 ^ 
 
 
 o — 
 
 _<,- 
 
 G 
 
 
 -- 
 
 ^^ 
 
 ^-^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 NATI 
 lOMMITT 
 
 )NAL a; 
 ;e for / 
 
 VISORY 
 ERONAUl 
 
 CS 
 
 8 /Z J6 20 
 
 Densiiy alfi+ude, ff 
 
 24- 
 
 Z8 
 
 SZ x/O" 
 
 F/gure S.- A/ormaf-potver climb at an mdicafed airspeed of 
 /60 niiJe^s per hour. Cur+iss A/o. 7/4-/C2-I2 four -blade 
 propeller on Pepubhc P-47C a/rp/ane. 
 
NACA ACR 
 
 L4L07 
 
 Fig. 
 
 /3, deg 
 
 8 IZ 16 20 
 
 Dens/fy alfifude , ff 
 
 SZx/0^ 
 
 f/gure 6- Normal -po^er climb ai an ind/cafed airspeed of 
 /6S miles per hour. Curfiss No. TI'!}--IC2-I2 -Four- blade 
 propel/e/- on fPepublic P-4-7C airplane.. 
 
NACA ACR No. L4L07 
 
 Figs. 7a, b 
 
 .J 
 
 
 5 ■' 
 
 
 
 -I 
 
 (a) Ran 20-/. 
 
 ■§ 
 
 to 
 
 ^.^R'lghf survey 
 
 J = 1.00 
 .Cp = J65 
 Ct = J32 
 r) =.799 
 M =.^40 
 Mt=.793 
 
 (b) Run 20-3. 
 
 Figune 7.- Thrusf-gradjng cunres for cJ/mh 
 at normal poi^er. /ndicafed airspeed , JGO 
 rnjles per hour. 
 
NACA ACR No. L4L07 
 
 Figs. 7c, d 
 
 K 
 
 ^ 
 
 
 .3 
 
 .2 
 
 .1 
 
 
 
 -./ 
 
 .J 
 
 
 ^ 
 
 ^ 
 
 
 
 -I 
 
 QJ 
 
 
 J = /.08 
 
 .Cp = J89 
 
 Cr = J40 
 
 yw = .2£3 
 .Mt = SI 2 
 
 Cc) Pun 20 -S. 
 
 - (b 
 
 ^/^/?f suryey 
 
 — ---^4^°T-^ --L J — 
 
 J =/./J 
 
 Ct ^150 
 y) -=.806 
 M = .28^ 
 
 NATIIINAL AD/ISORY 
 qOMMITTiE FOR A ;R0NAUTCS 
 
 -®— *- 
 
 /^ 
 
 ^o^; ^un 20-7. 
 Figure 7. " Conf/nuedL 
 
NACA ACR No. L4L07 
 
 Figs. 7e,f 
 
 k 
 
 ^ 
 
 ^ 
 
 ^ 
 
 ^ 
 
 (e) /?an 20-S- 
 
 (■f) R'un 20-/1. 
 Figure. ~7.- Continued. 
 
NACA ACR No. L4L07 
 
 Figs. 7g,h 
 
 k 
 ^ 
 
 
 K 
 Vi 
 
 ^ 
 
 (g) Pun 20-/2. 
 
 J =1.36 
 Cp = .JOJ\ 
 Ct = J78 
 >7 =-.799 
 M =.;54-Z 
 Mt=££/ 
 
 9 « 
 
 J. 2 
 
 rh) Run 20'IS. 
 Figure 7. - Concluded ■ 
 
MACA ACR No. L4L07 
 
 Fig. 8 
 
 § 
 
 § 
 
 
 S 
 
 -* 
 
 '"' m 
 
 s 
 
 
 
 
 s 
 "a 
 
 I 
 
 o 
 00 § 
 
 -^ 
 
 
 ^ 
 
 rK 
 
 
 No <o 
 
 I 
 
 -eo'^ 
 
 LO "-o 
 
 
 
 
 O 
 V. 
 Q 
 
 o 
 
 o 
 I 
 
 55 
 
 -f- 
 
 
 ^usz>^3c( '■U^houaioi.f^s ja/iadojfj 
 
NACA ACR No. L4L07 
 
 Fig. 9 
 
 
 <3 
 
 (0 
 
 5; 
 
 -k 
 
 
 «^ 
 
 to 
 
 s: 
 
 <s. 
 
 
 o 
 
 
 ^^ 
 
 i< 
 
 <b 
 
 <.) 
 
 ^ 
 
 ^ 
 
 V 
 
 
 
 <b 
 
 :5 V. Q 
 
 
NACA ACR No. L4L07 
 
 Fig. 10 
 
 f 
 
 
 
 
 
 
 
 
 
 
 
 
 
 SCRY 
 ONAUTIC 
 
 
 
 
 
 f 
 
 
 S2 ^ 
 
 <3 C3 
 
 
 lAL ADV 
 FOR AEI 
 
 
 
 -f 
 
 q/ 
 
 + 
 
 
 
 NATiOI 
 
 
 
 
 
 
 
 
 
 
 / 
 
 / + 
 
 
 
 
 tests 
 tests 
 
 
 
 
 
 
 
 
 — 
 
 <b (b 
 
 
 
 / 
 
 r 
 
 
 
 
 
 / 
 
 / 
 
 
 
 
 
 ■♦■ 
 
 
 / 
 
 W 
 
 
 
 
 
 
 
 / 
 
 
 
 
 
 
 
 
 / 
 
 / 
 
 
 
 
 
 
 
 
 / 
 / 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 i 
 i 
 
 ^ 
 Q 
 
 
 
 k 
 ^ 
 
 OS. 
 
 i 
 
 
 ^ 
 
 
 
 s:; 
 
 !^ 
 
 
 o 
 
 ^ 
 
 
 umber 
 speed. 
 
 ?; 
 
 
 5 ^ 
 
 ^ 
 
 •to 
 
 ^ cs 
 
 
 ^ 
 
 i^ ^ 
 
 
 '=^ 
 
 <0 Q) 
 
 
 •\ 
 
 II 
 
 
 
 
 -Q 
 
 5 
 S 
 
 
 
 s: 
 -Q 
 
 ^ (0 
 
 
 (o 
 
 
 1^ 
 
 C5 
 
 • 
 
 ^ 
 
 
 
 Q. 
 
 -K 
 
 
 ^ 
 
 Q 
 
 
 1 
 
 
 
 V 
 
 :>> 
 
 ^. 
 
 0) 
 
 
 
 Qj 
 
 .(b <l> 
 
 
 1 
 
 ^ u 
 
 
 1 '^^ 
 
 cv-^ 
 
 
 
 ^ 
 
 
 
 ^ ^ 
 
 pd3d9 tfdiof ^v U 
 
NACA ACR No. L4L07 
 
 Figs. 11a, b 
 
 \3 
 
 ~<5 
 
 
 
 'Xs 
 
 
 
 :/ 
 
 J- - /.S9 
 Cp = .34-3 
 Ct= J7/ 
 
 M - .4-31 
 Mi = .952 
 
 (a) Ruh 2^-G . 
 
 NATIONAL ADVISORY 
 COMMinEE FOR AERONAUTICS 
 
 Cb) k-'un 24-5. 
 Figure //. - Thrust -grading cun/es for Cp~0.3S. 
 
NACA ACR No. L4L07 
 
 Figs. llc,d 
 
 Cc) Run 24-1. 
 
 "55 
 
 
 .2 
 
 J 
 
 -I 
 
 (d) Run Z4-2, 
 Figure II. - Continued. 
 
NACA ACR No. L4L07 
 
 Figs . lie, f 
 
 J = 2.451 
 Cp = . JJ<9 
 
 ^ = .73S 
 M = .656 
 
 Mt=l.06A- 
 
 (e) Run Z4-3 
 
 ff) Run 2^-'^. 
 Figure II. ~ Concluded. 
 
NACA ACR No. L4L07 
 
 Fig. 12 
 
 -^ ^ > ^ ^. oq 
 II II ii II n M 
 
 w 
 
 CO 
 
 9 ^/S^ 96tD (9Sr?J 
 
 ^ 
 
 ^i 
 
 1' 
 
 ■'DP 
 
 I 
 
 I 
 
NACA ACR No. L4L07 
 
 Fig. 13 
 
 
 
 
 N 
 
 1 
 
 s 
 
 
 en 
 
 
 
 
 
 
 1 
 
 \ 
 
 
 10 
 
 SORY 
 tONAUTK 
 
 
 
 
 
 
 
 
 
 lAL ADV 
 FORAE 
 
 
 
 
 
 
 
 
 g 
 
 NATIO 
 
 
 
 
 
 
 
 \ 
 
 
 
 CJ> 
 
 
 
 
 
 
 \ 
 
 \ 
 
 
 
 
 
 
 
 
 
 1 
 
 \ 
 
 O 
 
 
 
 
 
 
 - 
 
 NT-/ 
 
 / 
 
 o 
 
 \o 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 < 
 
 o 
 
 
 
 
 
 
 
 
 o \ 
 
 ) 
 
 
 
 
 
 $5 
 
 
 
 
 I 
 
 \ 
 
 
 
 
 
 
 
 
 N 
 
 
 
 
 
 
 
 
 
 
 5 
 
 
 
 
 
 
 
 
 
 
 -v. 
 
 
 
 
 
 
 
 
 
 
 5 
 
 
 
 
 
 
 
 
 
 
 % 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^o 
 
 
 ^ 
 
 
 
 ^ 
 
 
 V) 
 
 
 5: 
 
 
 QJ 
 
 <N 
 
 > 
 
 ^o 
 
 «J 
 
 
 .■«N 
 
 
 s^ 
 
 
 V 
 
 
 qj 
 
 Cft 
 
 k 
 
 «V 
 
 >5i» 
 
 ' 
 
 ~N^ 
 
 
 <i) 
 
 
 SI 
 
 
 Q 
 
 
 V 
 
 ^ 
 
 Si. 
 
 ,0. 
 
 ^ 
 
 ^ 
 
 Q 
 
 
 
 * <b 
 
 -^ 
 
 y 
 
 Q 
 
 .-»» 
 
 o 
 
 s>. 
 
 -^ 
 
 s^ 
 
 
 
 <0 
 
 y 
 
 ^ . 
 
 k 
 
 ^R 
 
 <U 
 
 
 ^1 
 
 
 
 > s 
 
 
 o 
 
 
 <b 
 
 
 i^ 
 
 ^ 
 
 ^5i 
 
 
 , ;< 
 
 
 ' '-0 
 
 
 ^ 
 
 
 ^< 
 
 $ 
 
 
 
 ^ 
 
 
 
 § 
 
 ^ 
 
 
 ^.uaojad '■if '^ /fvu90ij.j.& Jd(f9d0J(j 
 
NACA ACR No. L4L07 
 
 Figs. 14a, b 
 
 .z 
 
 ^ 
 
 H 
 
 ^ 
 
 
 
 -./ 
 
 -z 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 7 = 2.G9 
 Cp^ J 4-1 
 Ct-.OZI 
 n ^.396 
 M ^ .7/1 
 Mi-^ 1-092 
 
 
 1 
 
 
 
 ^^ — -/?/^hf suri/e 
 
 V 
 
 
 
 
 1 
 
 
 / 
 
 f 
 
 
 
 
 
 
 
 / 
 
 r 
 
 -o-s- 
 
 TT-O- 
 
 ~~^ 
 
 
 + 
 
 -+-■♦ 
 
 — 1-~4 
 
 
 
 
 
 
 
 1 
 
 .4- 
 
 .( 
 
 O 
 
 z .<■ 
 
 ?^^ 
 
 1 
 
 /.z 
 
 1 
 
 
 
 1 
 
 V. 
 
 .lefi 
 
 - sc<n 
 
 'ey 
 
 
 
 
 
 
 
 
 
 
 ' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 / 
 
 
 
 
 
 
 
 
 
 
 
 
 (a) f?un 17-1. 
 
 
 >3 
 
 .?. 
 
 <1 
 
 c 
 c 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 7 =>^.7J 
 C^P = ./76 
 
 Ct= .031 
 7 =.47<S 
 M ^ .706 
 Mt=W77 
 
 1 
 
 3 
 
 
 
 
 
 
 
 ■Pigh-t 
 
 ^ SUt' 
 
 vey. 
 
 
 
 
 3 
 
 
 ^o-o- 
 
 
 
 
 
 
 4 
 / 
 
 V 
 
 ' — i^ 
 
 /e^/j 
 
 -uri/ei^ 
 
 
 ^>^ 
 
 ^,-^^ 
 
 --. 
 
 P'B<1>m^ 
 
 /T\ /fc 
 
 
 
 
 / 
 1 
 
 / 
 
 ^- 
 
 /. 
 
 \ ■■■■ 
 
 X 
 
 2 
 
 3 
 
 / 
 
 
 
 /- 
 
 z 
 
 -1 
 
 
 1 G 
 + / 
 // 
 
 
 
 
 
 «. 
 
 
 
 
 
 
 
 
 
 7 
 
 
 
 
 
 
 
 1 
 
 NATI 
 
 ;OMMin 
 
 )NAL A[ 
 I FOR A 
 
 VISORY 
 LKONAUT 
 
 cs 
 
 Figure /4-.~ ThroLsi- grading curi/es for runs af 
 J-^^JO and M<^0.7. 
 
NACA ACR No. L4L07 
 
 Figs. 14c, d 
 
 K 
 O 
 
 
 Cp = .2ZI 
 Cr^.04e 
 n ^.-567 
 M = .693 
 Mt= 1.070 
 
 (c) Pun I9-J8. 
 
 (d) Pan 21-9. 
 Figut'C /■4-. — Concluded. 
 
ii 
 
UNIVERSITY OF FLORIDA 
 
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 UNIVERSITY OF FLORIDA 
 DOCUMENTS DEPARTMENT 
 120 MARSTON SCIENCE LIBRARY 
 PO. BOX 117011 
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